This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We are currently investigating human kinetochore composition and organization using an affinity tagging strategy to isolate known and novel human kinetocore proteins and kinetochore protein complexes. We have developed a combined approach to examine the cellular localization of a protein and conduct a high affinity purification of that protein from human tissue culture cells (Localization and Affinity Purification - LAP tag). Using this approach, we have isolated more than 20 human kinetochore proteins, including at least 10 novel kinetochore proteins. This ongoing analysis will attempt to characterize the full range of human kinetochore proteins and examine their interactions and organization.